X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=kernel%2Fkprobes.c;h=1fbf466a29aab6ca0dfe1cf6e5d6ac16fba546d8;hb=ecd68853b852cdafb138f9c437f3a751fe7dc381;hp=34a885bb82e0d94a38a7ebec8e8014cf2dc197d1;hpb=a0d50069ed3620e9a4d8939bbc3e0d5a692ab58a;p=powerpc.git diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 34a885bb82..1fbf466a29 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -48,7 +48,7 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; -DECLARE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ +DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; @@ -323,10 +323,10 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) } /* - * This function is called from exit_thread or flush_thread when task tk's - * stack is being recycled so that we can recycle any function-return probe - * instances associated with this task. These left over instances represent - * probed functions that have been called but will never return. + * This function is called from finish_task_switch when task tk becomes dead, + * so that we can recycle any function-return probe instances associated + * with this task. These left over instances represent probed functions + * that have been called but will never return. */ void __kprobes kprobe_flush_task(struct task_struct *tk) { @@ -336,7 +336,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) unsigned long flags = 0; spin_lock_irqsave(&kretprobe_lock, flags); - head = kretprobe_inst_table_head(current); + head = kretprobe_inst_table_head(tk); hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { if (ri->task == tk) recycle_rp_inst(ri); @@ -344,23 +344,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) spin_unlock_irqrestore(&kretprobe_lock, flags); } -/* - * This kprobe pre_handler is registered with every kretprobe. When probe - * hits it will set up the return probe. - */ -static int __kprobes pre_handler_kretprobe(struct kprobe *p, - struct pt_regs *regs) -{ - struct kretprobe *rp = container_of(p, struct kretprobe, kp); - unsigned long flags = 0; - - /*TODO: consider to only swap the RA after the last pre_handler fired */ - spin_lock_irqsave(&kretprobe_lock, flags); - arch_prepare_kretprobe(rp, regs); - spin_unlock_irqrestore(&kretprobe_lock, flags); - return 0; -} - static inline void free_rp_inst(struct kretprobe *rp) { struct kretprobe_instance *ri; @@ -449,22 +432,35 @@ static int __kprobes in_kprobes_functions(unsigned long addr) return 0; } -int __kprobes register_kprobe(struct kprobe *p) +static int __kprobes __register_kprobe(struct kprobe *p, + unsigned long called_from) { int ret = 0; struct kprobe *old_p; - struct module *mod; + struct module *probed_mod; if ((!kernel_text_address((unsigned long) p->addr)) || in_kprobes_functions((unsigned long) p->addr)) return -EINVAL; - if ((mod = module_text_address((unsigned long) p->addr)) && - (unlikely(!try_module_get(mod)))) - return -EINVAL; + p->mod_refcounted = 0; + /* Check are we probing a module */ + if ((probed_mod = module_text_address((unsigned long) p->addr))) { + struct module *calling_mod = module_text_address(called_from); + /* We must allow modules to probe themself and + * in this case avoid incrementing the module refcount, + * so as to allow unloading of self probing modules. + */ + if (calling_mod && (calling_mod != probed_mod)) { + if (unlikely(!try_module_get(probed_mod))) + return -EINVAL; + p->mod_refcounted = 1; + } else + probed_mod = NULL; + } p->nmissed = 0; - down(&kprobe_mutex); + mutex_lock(&kprobe_mutex); old_p = get_kprobe(p->addr); if (old_p) { ret = register_aggr_kprobe(old_p, p); @@ -481,23 +477,29 @@ int __kprobes register_kprobe(struct kprobe *p) arch_arm_kprobe(p); out: - up(&kprobe_mutex); + mutex_unlock(&kprobe_mutex); - if (ret && mod) - module_put(mod); + if (ret && probed_mod) + module_put(probed_mod); return ret; } +int __kprobes register_kprobe(struct kprobe *p) +{ + return __register_kprobe(p, + (unsigned long)__builtin_return_address(0)); +} + void __kprobes unregister_kprobe(struct kprobe *p) { struct module *mod; struct kprobe *old_p, *list_p; int cleanup_p; - down(&kprobe_mutex); + mutex_lock(&kprobe_mutex); old_p = get_kprobe(p->addr); if (unlikely(!old_p)) { - up(&kprobe_mutex); + mutex_unlock(&kprobe_mutex); return; } if (p != old_p) { @@ -505,7 +507,7 @@ void __kprobes unregister_kprobe(struct kprobe *p) if (list_p == p) /* kprobe p is a valid probe */ goto valid_p; - up(&kprobe_mutex); + mutex_unlock(&kprobe_mutex); return; } valid_p: @@ -521,10 +523,11 @@ valid_p: cleanup_p = 0; } - up(&kprobe_mutex); + mutex_unlock(&kprobe_mutex); synchronize_sched(); - if ((mod = module_text_address((unsigned long)p->addr))) + if (p->mod_refcounted && + (mod = module_text_address((unsigned long)p->addr))) module_put(mod); if (cleanup_p) { @@ -547,7 +550,8 @@ int __kprobes register_jprobe(struct jprobe *jp) jp->kp.pre_handler = setjmp_pre_handler; jp->kp.break_handler = longjmp_break_handler; - return register_kprobe(&jp->kp); + return __register_kprobe(&jp->kp, + (unsigned long)__builtin_return_address(0)); } void __kprobes unregister_jprobe(struct jprobe *jp) @@ -557,6 +561,23 @@ void __kprobes unregister_jprobe(struct jprobe *jp) #ifdef ARCH_SUPPORTS_KRETPROBES +/* + * This kprobe pre_handler is registered with every kretprobe. When probe + * hits it will set up the return probe. + */ +static int __kprobes pre_handler_kretprobe(struct kprobe *p, + struct pt_regs *regs) +{ + struct kretprobe *rp = container_of(p, struct kretprobe, kp); + unsigned long flags = 0; + + /*TODO: consider to only swap the RA after the last pre_handler fired */ + spin_lock_irqsave(&kretprobe_lock, flags); + arch_prepare_kretprobe(rp, regs); + spin_unlock_irqrestore(&kretprobe_lock, flags); + return 0; +} + int __kprobes register_kretprobe(struct kretprobe *rp) { int ret = 0; @@ -564,6 +585,9 @@ int __kprobes register_kretprobe(struct kretprobe *rp) int i; rp->kp.pre_handler = pre_handler_kretprobe; + rp->kp.post_handler = NULL; + rp->kp.fault_handler = NULL; + rp->kp.break_handler = NULL; /* Pre-allocate memory for max kretprobe instances */ if (rp->maxactive <= 0) { @@ -587,7 +611,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp) rp->nmissed = 0; /* Establish function entry probe point */ - if ((ret = register_kprobe(&rp->kp)) != 0) + if ((ret = __register_kprobe(&rp->kp, + (unsigned long)__builtin_return_address(0))) != 0) free_rp_inst(rp); return ret; } @@ -609,12 +634,12 @@ void __kprobes unregister_kretprobe(struct kretprobe *rp) unregister_kprobe(&rp->kp); /* No race here */ spin_lock_irqsave(&kretprobe_lock, flags); - free_rp_inst(rp); while ((ri = get_used_rp_inst(rp)) != NULL) { ri->rp = NULL; hlist_del(&ri->uflist); } spin_unlock_irqrestore(&kretprobe_lock, flags); + free_rp_inst(rp); } static int __init init_kprobes(void)